1. Field of the Invention
The present invention relates to a method and apparatus for forming an amorphous silicon film.
2. Description of the Related Art
An amorphous silicon film is used for embedding of a contact hole or line of a semiconductor integrated circuit apparatus, etc. A method of forming an amorphous silicon is disclosed in, for example, Patent References 1 and 2. Specifically, Patent Reference 2 discloses a method of obtaining a conductive layer having an even surface by decomposing disilane at 400 to 500° C.
Recently, accompanying high integration of a semiconductor integrated circuit apparatus is miniaturization of a contact hole or line.
In order to embed a miniaturized contact hole or line, it is essential to further thin an amorphous silicon film.
Disilane is a film-forming material that is easily thinned, but it is difficult to obtain satisfactory step coverage in an amorphous silicon film formed by using disilane. In this regard, it is easy to obtain satisfactory step coverage from silane, compared to disilane, but silane requires a long incubation time, and thus is a film-forming material that is difficult to be thinned.
Furthermore, it is important to form an amorphous silicon film having an even surface, along with a thin thickness, because if a contact hole or line is embedded with an amorphous silicon film having an uneven surface, a void may be generated.
3. Prior Art Reference
(Patent Reference 1) Japanese Laid-Open Patent Publication No. sho 63-29954
(Patent Reference 2) Japanese Laid-Open Patent Publication No. hei 1-217956